Last week when I was home for Thanksgiving, I caught a report on the Philly CBS affiliate about what is apparently a new trend in holiday gift giving: gift registries. This hybrid of children’s Christmas lists and wedding registries, where adults register their holiday gift desires at places like MyRegistry.com and then share those registries with their friends, certainly cuts down on the “deadweight loss” of unwanted gifts. But what are we to make of the etiquette of these things? A welcome innovation? Tacky and presumptuous? I lean towards the latter, but then again, I never stopped writing the old fashioned kind of Christmas list.